The present invention relates to systems for checking the pressure of the tyres of the wheels of motor vehicles (TPMS, Tyre Pressure Monitoring System), with a pressure sensor on each wheel, as well as an emitter to transmit the pressure to a control unit.
In these systems, the emission signals comprise data for identification of the sensors, and, if the wheels of a vehicle were never changed, a simple initial process in the factory for learning matching of the signals and wheels would make it possible to determine the location relative to the chassis of the vehicle, of the sensors and thus of the faulty tyres. However, the wheels of a vehicle may be replaced and changed over from time to time, for example when “snow” tyres are fitted.
The applicant has therefore attempted to solve the problem of discrimination of the pressure sensors for the motor vehicle wheel tyres.
Solutions to this problem are already known.
Thus, EP 806 307 teaches association with the signal of a wheel pressure sensor, of the data relating to the speed of rotation of the wheel, determined on a dual basis, i.e. firstly from the wheel itself, and secondly from the chassis of the vehicle, which provides the positioning reference.
A solution of this type is not satisfactory, since it is very cumbersome to implement, with a plurality of devices for determination of the speed of rotation of the wheels and devices to receive the signals of the pressure sensors.